Ultraviolet scattering agent and application therefor

Abstract

Provided is an ultraviolet scattering agent characterized by comprising at least one type of elliptical or needle-like polymer particles (A), wherein (1) the average (LAV) of the major axis (L) in a two-dimensional projection diagram obtained by radiating light from a direction perpendicular to the major-axis direction is 0.1 to 80 microns, (2) the average (DAV) of the minor axis (D) in a two-dimensional projection diagram obtained by radiating light from a direction perpendicular to the major-axis direction is 0.05 to 40 microns, and (3) the average (PAV) of the aspect ratio (L / D) calculated from the major axis (L) and the minor axis (D) is 2 to 30.

Description

technical field [0001] The present invention relates to ultraviolet (UV) scattering agents and their use. Background technique [0002] Polymer particles and inorganic particles having a micron size are used as fillers and objects to be inspected in various fields such as electronic and electrical materials, optical materials, paints, inks, building materials, biological and medical materials, and cosmetics. In recent years, particularly, the development of irregularly shaped microparticles other than spherical ones has been actively carried out, and application development has been increasingly carried out in order to impart various properties such as optical characteristics and texture. The present inventors have also developed elliptical or needle-shaped polymer particles with a high aspect ratio, and have developed particles that are more excellent than conventional spherical particles in various characteristics such as concealment, light scattering, and hand feeling (pa...

AI Technical Summary

Problems solved by technology

[0004] Generally, if the amount of UV absorber is increased, the effect will be improved, but since the UV shielding mechanism is mainly absorption, there is a disadvantage that only UV in a certain wavelength range can be shielded, and there may be problems in durability

In addition, if UV absorbers are used in cosmetics, etc., for people with weak skin, there may be effects on the human body such as rough skin and rashes.

[0005] On the other hand, UV scattering agents made of inorganic particles such as zinc oxide and titanium oxide generally have a high UV scattering effect, but it is difficult to disperse and maintain them in the state of primary particles, and they often exist as aggregates, resulting in concealment. Disadvantages of over-elevation

In addition, there is a disadvantage that glossiness is impaired even if only a small amount is added

[0006] Compared with organic materials, inorganic materials have a large specificity, and when used in films, molded products, etc., they are difficult to be compatible with resins, so there may be disadvantages in terms of light weight, crackability, etc.

In addition, in cosmetics, in order to maintain dispersion, it is sometimes necessary to use a large amount of surfactant, and the use of a large amount of surfactant is not preferable from the viewpoint of preventing rough skin and skin aging.

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